The present invention relates to musical instruments in general, and more particularly to improvements in electronic musical instruments, especially organs. Still more particularly, the invention relates to improvements in keyboard units of organs or analogous musical instruments.
It is known to assemble the keyboard unit of a musical instrument (hereinafter called organ for short) in such a way that one or more parts thereof are movable from operative positions to second positions in which the components (e.g., keys, stops, switches or the like) on such parts are accessible for inspection, repair, adjustment or replacement. In accordance with a presently known proposal, the housing or casing of the keyboard unit supports several pivotable carriers each of which includes an elongated hollow circumferentially complete profiled member and at least one plate-like support which is secured to the respective profiled member by one or more screws and nuts and serves as a means for mounting the keys of a keyboard, switches, stops, drawbars and analogous components. The ends of the profiled members are turnably mounted in the housing. The means for turnably mounting the profiled members includes arms which are welded to the respective ends of the associated profiled members and are formed with round holes for screws which constitute fulcra and extend into the side walls of the housing. Furthermore, the end portions of each profiled member are welded to additional arms which extend forwardly and overlie shoulders or steps provided therefor on the side walls of the housing. The profiled members have a rectangular cross-sectional outline and are formed with tapped holes which are machined into two spaced-apart sections of the respective profiled members to take relatively long screws forming part of means for fastening the aforementioned plate-like supports to the associated profiled members. The exact locations of tapped holes depend on the dimensions of the supports.
The just described conventional keyboard units exhibit many advantages. Thus, all or nearly all components which are mounted in or on a support are readily accessible as soon as the support is pivoted to its second position. Such components may include electrical or electronic devices which are connected with conductors, cables or the like. However, the machining and mounting of the parts in such keyboard units must be carried out with a high degree of precision in order to insure that the visible or accessible portions of switches, keys, drawbars and analogous components will assume optimum positions with respect to each other and with respect to the housing when the keyboard unit is fully assembled. Thus, the ultimate positions of such components depend, to a large degree, on the tolerances of machining the constituents of the housing, of the carriers and the components which are secured to the supports of the carriers. Moreover, the aforementioned holes for the fulcra and the tapped bores of the profiled members must also be machined, and their positions selected, with a high degree of accuracy. The situation is aggravated if the keyboard unit forms part of an organ which is to be assembled by the purchaser, i.e., if the parts of the keyboard unit are sold in dismantled condition not unlike the parts of an erector kit. An unskilled purchaser of a dismantled keyboard unit is highly unlikely to be capable of compensating for machining tolerances and/or of drilling holes or tapped bores with a degree of accuracy which is needed to insure proper functioning of mobile components as well as an eye-pleasing appearance of the assembled unit. Another drawback of the aforedescribed keyboard units is that the profiled members and the plate-like supports of the carriers are quite heavy and bulky which presents problems in connection with packaging and shipment.